How to Use Java String.format for Numbers with Localization?

How can I format numbers with localization in Java using String.format?

String formattedNumber = String.format(Locale.US, "%,.2f", 1234567.89); // Output: "1,234,567.89".

Java provides a built-in mechanism to format numbers according to different locales using the String.format method. This feature allows developers to create user-friendly applications that adhere to local number formatting conventions, including thousands separators, decimal points, and currency symbols.

import java.util.Locale;

public class Main {
    public static void main(String[] args) {
        // Formatting a number for the US locale 
        double number = 1234567.89;
        String formattedNumber = String.format(Locale.US, "%,.2f", number);
        System.out.println(formattedNumber); // Output: 1,234,567.89

        // Formatting a number for the French locale
        String formattedNumberFR = String.format(Locale.FRANCE, "%,.2f", number);
        System.out.println(formattedNumberFR); // Output: 1 234 567,89
    }
}

Causes

• Inconsistent number representation across different countries.
• Applications not adhering to local customs may confuse users.

Solutions

• Use the Locale class to specify the desired locale for formatting numbers.
• Utilize the String.format method with appropriate format specifiers to ensure proper number formatting.

Mistake: Using a locale that does not match the user's settings.

Solution: Always check the user's locale and format numbers accordingly.

Mistake: Forgetting to specify the Locale in String.format method.

Solution: Include the Locale parameter to ensure correct formatting.